STUDY ON REDUCING AND MELTING BEHAVIOR OF MILL SCALE/PETROLEUM COKE BLEND
ESTUDO DO COMPORTAMENTO DE REDUÇÃO E FUSÃO DE MISTURAS DE CAREPA/COQUE DE PETRÓLEO
Flores, Bruno Deves; Flores, Ismael Vemdrame; Bagatini, Mauricio Covcevich; Osório, Eduardo; Vilela, Antônio Cezar F.
http://dx.doi.org/10.4322/tmm.2013.050
Tecnol. Metal. Mater. Min., vol.10, n4, p.365-374, 2013
Abstract
Self-reducing tests were carried out under isothermal and non-isothermal condition in a muffle furnace, aiming to assess the reduction and melting of a self-reducing blend of mill scale and petroleum coke (85-15% in weight).The products obtained were analyzed by mass loss and wet analysis. Further investigations for the products from the non-isothermal condition were done by X-ray diffraction, nude eye inspection and carbon analyzer. It was observed that mass loss fraction and metallization degree are directly related and both increase with time and temperature. In the non-isothermal maximum mass loss was achieved in 8 minutes, reaching metallization degrees above 90%. It was observed that the reduction of iron oxide occurs mainly in solid state and the smelting of the samples is directly related to the iron carburization process. Thus, the use of self-reducing mixtures shows a possible way to recycle mill scale.
Keywords
Mill scale, Self-reduction, Iron carburization
Resumo
Testes de autorredução em condições isotérmicas e não isotérmicas em forno mufla, foram propostos para avaliar a redução e fusão de uma mistura autorredutora de carepa e coque de petróleo (85-15% em massa). Os produtos obtidos foram analisados através de análises de perda de massa e via úmida. Para os produtos obtidos nas condições não isotérmicas também foram realizadas análises de difração de raios-X, inspeção a olho nu e análise de carbono. Observou-se que a fração reagida e o grau de metalização obtidos estão diretamente relacionados e ambos aumentam com o tempo e temperatura. Os ensaios não isotérmicos levaram 8 minutos para atingir a perda de massa máxima da mistura, alcançando graus de metalização superiores a 90%. Verificou-se que a redução dos óxidos de ferro ocorre principalmente no estado sólido e que a fusão das amostras está diretamente relacionada com o processo de carburação do ferro. Desta forma, o uso de misturas autorredutoras indica uma possibilidade de reciclagem de carepa.
Palavras-chave
Carepa, Autorredução, Carburação do ferro
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